What about the Others?

Ok, so either I am confused or the writers totally let this one go. What about the Others? Were the Others created when Jacob gave Richard the task of being the adviser? If so then who were the other Others that child MIB went to live with? Also, what purpose did the Others serve if Jacob had already called the candidates to the island? The Others kidnapped people and killed some, yet they were working for Jacob and yet Jacob called the candidates to the island? Doesn't make sense to me. Any thoughts?